Image forming apparatus with charge member and image supporting member having specific characteristics

Abstract

An image forming apparatus includes: an image supporting member; a charge member for charging a surface of the image supporting member; an exposure member for forming a latent image on the surface of the image supporting member charged by the charge roller; a developer supporting member for developing the latent image formed by the exposure member to form a toner image; and a transfer member for transferring the toner image formed by the developer supporting member to a medium. The image supporting member has a dark decay characteristic ratio of 95% or less relative to charges having a polarity opposite to that of a charge voltage applied by the charge member.

1. An image forming apparatus, comprising:
 an image supporting member having a dark decay characteristic ratio of 95% or less relative to charges, said image supporting member including a charge transporting layer, said charge transporting layer being formed of a charge transporting material formed of a hydrazon compound and a binder resin formed of polycarbonate so that a ratio of the hydrazon compound relative to polycarbonate is between 0.30 and 0.47; 
 a charge member for applying a charge voltage to the image supporting member to charge a surface of the image supporting member, said charge voltage having polarity opposite to that of the charges; 
 an exposure member for forming a latent image on the surface of the image supporting member; 
 a developer supporting member for developing the latent image to form a toner image; and 
 a transfer member for transferring the toner image to a medium, 
 wherein said image supporting member includes a charge generating layer formed of a charge generating material of a phthalocyanine type. 
 
     
     
       2. The image forming apparatus according to  claim 1 , wherein said charge member is arranged to charge the surface of the image supporting member with a negative potential, said image supporting member having the dark decay characteristic ratio of 95% or less relative to positive charges. 
     
     
       3. The image forming apparatus according to  claim 1 , wherein said image supporting member has the dark decay characteristic ratio defined by the following equation;
   ρ=( Vb/Va )×100 
 
       where Va is a surface potential of the image supporting member right after the image supporting member is charged, and Vb is a surface potential of the image supporting member at 10 seconds after the image supporting member is charged. 
     
     
       4. The image forming apparatus according to  claim 2 , wherein said image supporting member has the dark decay characteristic ratio defined by the following equation;
   ρ=( Vb/Va )×100 
 
       where Va is a surface potential of the image supporting member right after the image supporting member is charged, and Vb is a surface potential of the image supporting member at 10 seconds after the image supporting member is charged.